⏵ Course guide · Oahu's five-loop 100
The HURT 100 sends its field around five loops of roughly 19.5 miles each through the Makiki, Manoa, and Nuuanu valleys above Honolulu, about 24,500 feet of climbing on 99% singletrack, tropical roots, mud, and 22 stream crossings. The Hawaiian Ultra Running Team built this race, in their own words, for the "adventurous and well-prepared." I will walk you through the loop structure and terrain first, then give you a pacing and fueling plan built for technical, repeated tropical trail, plus free tools to dial in your own numbers.
These facts come from the official Book of HURT rulebook. HURT revises exact course and cutoff specifics some years, so confirm the current Book of HURT on hurt100.com before you commit.
HURT runs five loops of roughly 19.5 miles each, connecting the Makiki, Manoa, and Nuuanu aid stations on trails through the valleys above Honolulu. Each aid station gets visited five times over the course of the race.
The course elevation itself only ranges from 300 to 1,900 feet, a modest band on paper. But running the same steep, technical loop five times stacks up to roughly 24,500 feet of cumulative climbing, and the same amount of descent. This is a race decided by how you manage repetition and cumulative fatigue, not by surviving one defining mountain.
Nearly the entire course, 99%, runs on singletrack through roots, mud, and tropical rainforest, with 22 stream crossings along the way. Footing here punishes anyone expecting to run at a flat-ground pace, and the humidity of an Oahu forest adds a fatigue factor that raw elevation numbers do not capture.
HURT does not fill by first-come registration. Applicants are sorted into categories, HURT veterans with three or more prior finishes, runners waitlisted in the past but never selected, and everyone else, then entered into a weighted drawing where prior history with the race earns more chances. The field lands at roughly 135 to 140 starters. Plan your application timeline around the lottery, not around beating other runners to a signup page.
With a 36 hour cutoff and a course record just under 20 hours, the gap between the fastest and the average finisher here is enormous, which tells you how much this terrain punishes anything but honest, sustainable pacing.
Because the same roughly 19.5-mile loop repeats five times, an aggressive first loop borrows directly from the legs you need for loops four and five. A grade-adjusted pace target, applied to the technical singletrack rather than a flat-ground number, gives you an honest read on what effort you can actually repeat five times.
The loop format gives you real data fast: after loop one or two, a vert-aware finish prediction built off your actual splits is far more honest than any generic 100 mile estimate, especially on terrain this technical. Check that projection against the 36 hour cutoff early, while you still have room to adjust your effort rather than your expectations.
⏵ Free tools to pace this course
A 36 hour clock and technical, repeated terrain likely take most finishers well past a full day and into a full night on trail, through Oahu's heat and humidity even up in the valleys.
Aim for roughly 60 to 90 grams of carbohydrate per hour. Each of the three aid stations gets visited five times over the race, so use that frequency to keep your intake consistent rather than gambling on carrying enough between long, remote gaps like some 100s require.
Sodium in the 300 to 700-plus mg per liter range covers most runners, leaning toward the higher end given Oahu's humidity, which can sap you even on a course that never gets truly high in elevation. Heat and humidity, not altitude, are the environmental factors that matter most here.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a humid Oahu day and night with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.
⏵ Train for it with Summit Line
Get a race-day plan built around YOUR fitness, this exact five-loop climbing profile, and your projected splits. Summit Line reads your real training, builds a plan for repeated technical climbing in the heat, and rehearses your fueling so race day is something you execute, not guess at.
HURT is widely considered one of the hardest 100 milers in the country, and its own organizers describe it as "designed for the adventurous and well-prepared." Five loops of roughly 19.5 miles each stack up to about 24,500 feet of climbing on 99% singletrack, tropical roots and mud, and 22 stream crossings through the Makiki, Manoa, and Nuuanu valleys above Honolulu. Course records sit at 19 hours 35 minutes for men and 23 hours 26 minutes for women, against a 36 hour cutoff, which tells you how much slower most finishers move on this terrain than the raw mileage suggests.
The official Book of HURT lists roughly 24,500 feet of cumulative elevation gain, and the same amount of loss, over the full 100 miles. Course elevation itself only ranges from 300 to 1,900 feet, which means the climbing comes almost entirely from repetition: five loops of the same steep, technical terrain rather than one long sustained ascent. That repetition is part of what makes HURT so demanding.
With a 36 hour time limit and technical, tropical terrain slowing almost everyone down, plan for a long day and at least one full night on trail, likely somewhere in the 24 to 36 hour range. Aim for roughly 60 to 90 grams of carbohydrate per hour, and sodium in the 300 to 700-plus mg per liter range given Oahu's heat and humidity even at elevation. Each of the three aid stations is visited five times over the race, so you have frequent, predictable chances to reset your intake rather than carrying huge reserves between stops. Build your numbers with the free ultra fueling calculator before race day.
The overall time limit is 36 hours. The official Book of HURT lays out specific late-race checkpoint cutoffs for the final loop, but the earlier splits are not something we can verify here, so pull the current cutoff sheet from hurt100.com before you build your pacing plan. Given the roughly 24,500 feet of cumulative climbing on technical terrain, build in real margin, especially since the course record itself sits at just under 20 hours, meaning most finishers need considerably more time than the fastest.
HURT runs a weighted lottery rather than open registration. Applicants are sorted into categories, including a reserved category for HURT veterans with three or more prior finishes and a category for runners waitlisted in the past but never selected, with the remaining spots going to everyone else. Each applicant earns entries in a weighted drawing based on their history with the race, and the field lands at roughly 135 to 140 starters. If you are new to HURT, expect the lottery, not raw speed of registering, to determine your entry.
No, and HURT does not pretend otherwise: it is designed, in its own words, "for the adventurous and well-prepared." Five loops of roughly 19.5 miles each, about 24,500 feet of climbing on technical, root-and-mud singletrack, tropical heat and humidity, and 22 stream crossings make this a serious test even for experienced trail ultrarunners. If you are considering HURT as your first 100, build significant technical trail and heat experience first, and treat the 36 hour cutoff, generous on paper, as a real limit given how much this terrain slows even strong runners.
This guide is independent and for planning only. The course details, dates, cutoffs, and entry rules come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.